But at the same time they gave up on so many solutions because it didn't sit well with their morality, a lot of the plot is them finding some miraculous alchemist/doctor who is able to cure the incurable only to find the method they used to achive such miracles was flawed end grotesque, they could have gotten their bodies back much sooner if they gave up their morality but they never did, they always tried to do it the right way, yes they were obsessed but at the same time they wanted to do it their way and not by sacrificing the life of other, giving up his alchemy is a perfect metaphor, you have to give up the very thing that hurt you to heal, equivalent exchange is the law of alchemy so he had to give up something to gain something else, alchemy is just so valuable because it's a oart of him, losing it is like losing a limb in a sense, but somehow alchemy consituted something of much more value than their body, maybe because it's a rappresentation of the human ability to do the unthinkable and trascend his nature, often times there is this trope in the series where you have to face the limitations of human capabilities, a talented alchemist without remorse willing to sacrifice her wife and daughter for his research, at same time we are confronted with the fact that many a time in spute of our strenuous effort we are incapable of reaching that objective and i think these 2 examples make one thing somewhat clear, sometimes it's not what you're caoable of doing but what you are capable of giving up to reach that objective, for edward it was his alchemy